ISSN:
0947-6539
Keywords:
crystal structure
;
density functional calculations
;
polyarsenido complexes
;
polyphosphido complexes
;
Zintl anions
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The Zintl anion P3-7 reacts with complexes of transition metal halides to form multinuclear metal phosphorus clusters. Reaction of Li3P7·3 DME with [FeCp(CO)2Br] or [NiCl2(PBu3)2] leads to the formation of [P7{FeCp(CO)2}3] (1) and [{Ni(PBu3)2}4P14] (2), respectively. X-ray structure determinations show that in 1 the P7 cage of Li3P7 remains intact but in 2 a P14 framework is formed by linkage of two norbornadiene-like P7 units. The P14 skeleton coordinates to four Ni(PBu3)2 groups. LiCp* and CoCl2 react with P7(SiMe3)3 to give [(Cp*Co)3-(P2)3] (3) with three Cp*Co groups bridged by P2 units. Reaction of FeCl2 and LiCp* with P7(SiMe3)3 yields [(Cp*Fe)3P6][FeCl3(thf)] (4) or [(Cp*Fe)3{n3-P3)Fe}P6] (5), depending on the reaction conditions. In 4 the structure of the Fe3P6 core of the [(Cp*Fe)3P6]+ cation is comparable to closo-B9H92-, while in 5 the Fe4P6 core does not obey the Wade rules. The unusual Co-As cluster [Co6As12(PEt2Ph)6] (6), prepared from K, As, and [CoCl2(PEt2-Ph)2], can be described as a Co6As6 heteroicosahedron linked to two Co3As3 octahedra by common Co3 faces. A theoretical treatment within the density functional approximation reproduces the experimental structures of 2 and 6 and allows an interpretation of molecular electronic structures. In 2 one finds P-P double bonds that are delocalized to some extent into vacant Ni AOs. For the cage compound 6 the Co 3 d AOs participate in cage bonding and 38 electrons can be assigned to cage bonds; this is in accord with the (2N + 2) rule for 18-atom cages but not with the usual electron counting rules.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chem.19960020217
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